Abstract:
A research project on laboratorial characterization of the breach processes involved in the
failure by overtopping of earth dams is currently ongoing at LNEC and IST. The breach
evolution process is a complex phenomenon which requires the understanding of both
hydraulic and geotechnical components involved. Laboratorial tests allowed relating the
dynamics of the breach with the hydraulic and geotechnical properties of the embankments
and understanding how the latter influence the failure mechanisms. In this paper four
different approaches for estimating breach hydrographs are presented. Two are based on: i)
stage-discharge relations; and ii) water-volume balances within the reservoir. The other two
constitute a novel estimating method and are both based on velocity field maps, obtained
from the application of an LSPIV algorithm and on breach area detection, delineated with the
aid of a laser sheet. The technique used for combining the instrumentation and measuring
methods in these different approaches for breach hydrographs estimation is herein
scrutinized.
